CHICAGO (AP) — Joe Biden defended his civil rights record on Friday, pledging to be a “president who stands against racism, the forces of intolerance.”

The former vice president and Democratic White House hopeful was in Chicago a day after his 2020 rival California Sen. Kamala Harris delivered a blistering attack at their first presidential debate in Miami. She blasted him for recently highlighting his work with segregationist senators and his past opposition to busing.

“I heard, and I listened to, and I respect Sen. Harris,” Biden said in an address to the Rev. Jesse Jackson’s Rainbow PUSH Coalition, a multicultural organization promoting social justice. “But we all know that 30 seconds to 60 seconds on a campaign debate exchange can’t do justice to a lifetime commitment to civil rights.”

Biden said he never opposed the busing of students to desegregated schools in the 1970s, arguing it was a state’s rights issue. Instead, Biden said Friday that he has for decades understood that it was up to the federal government to impose measures designed to prevent racism on states that were often unwilling.

Friday’s address may help Biden shore up his support with African Americans, a key demographic that helped him build an early lead in Democratic primary polls. The crowd applauded parts of his defense of his record.